get_blog_id_from_url( string $domain, string $path = '/' ): int
- Since
- MU (3.0.0)
- Source
wp-includes/ms-functions.php:350
Description
On a subdirectory installation like example.com/blog1/, $domain will be the root 'example.com' and $path the subdirectory '/blog1/'. With subdomains like blog1.example.com, $domain is 'blog1.example.com' and $path is '/'.
Compatibility
- WordPress
- since MU (3.0.0)
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.
Parameters
$domainstring- Website domain.
$pathstringoptional- Not required for subdomain installations. Default '/'.Default:
'/'
Return value
int- 0 if no blog found, otherwise the ID of the matching blog.
Performance profile
How much work a call to get_blog_id_from_url() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Light
- Scaling
- Constant
- Instructions
- 22–47
- Plugin surface
- None
- Called by
- 0
Only touches the object cache, via wp_cache_get().
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 60.
Nothing here hands control to plugin code.
Nothing in core calls this; the cost is only what you spend yourself.
What it touches
- cacheobject cache
wp_cache_get()called directly
What one call costs · 2 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost get_blog_id_from_url() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 22–24 | strtolower(), strtolower(), md5(), wp_cache_get() |
$id !== -1 | 47 | strtolower(), strtolower(), md5(), wp_cache_get(), get_sites(), array_shift(), md5(), wp_cache_set() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 60 instructions, 22–47 executed per call, 3 branches. The work does not change between versions.
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Uses · 3
- wp_cache_get()Retrieves the cache contents from the cache by key and group.
- get_sites()Retrieves a list of sites matching requested arguments.
- wp_cache_set()Saves the data to the cache.
Source code
function get_blog_id_from_url( $domain, $path = '/' ) { $domain = strtolower( $domain ); $path = strtolower( $path ); $id = wp_cache_get( md5( $domain . $path ), 'blog-id-cache' ); if ( -1 === $id ) { // Blog does not exist. return 0; } elseif ( $id ) { return (int) $id; } $args = array( 'domain' => $domain, 'path' => $path, 'fields' => 'ids', 'number' => 1, 'update_site_meta_cache' => false, ); $result = get_sites( $args ); $id = array_shift( $result ); if ( ! $id ) { wp_cache_set( md5( $domain . $path ), -1, 'blog-id-cache' ); return 0; } wp_cache_set( md5( $domain . $path ), $id, 'blog-id-cache' ); return $id;}Changelog
Introduced in MU (3.0.0). Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
About this page
- Parsed data
- Generated from the wordpress-develop 7.0.4 tag, from
src/wp-includes/ms-functions.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.